This epidemiologic study extends observations on 30,000 living former students from Harvard and 13,000 from the University of Pennsylvania to identify patterns of physical activity conducive to the avoidance or delay of hypertensive-arteriosclerotic diseases in middle life. Prospective observations utilize both historical and ongoing perspectives to: l. Identify the type, frequency, duration, and intensity of activities that predispose to reduced risk of first heart attack, stroke, and other cardiovascular diseases primary prevention. 2. Examine changes in physical activity patterns and other key aspects of life style for their relationships to heart attack risk. Patterns of exertion favoring coronary well-being will be studied in successive age group ranging 45-80 years. 3. Test competing hypotheses of benefit, (a) protection vs. selection and (b) average vs. peak levels of energy output. 4. Assess patterns of physical activity associated with prevention of heart attack recurrence and with survival (secondary prevention). 5. Examine sociopsychological and other risk factors for confounding and interacting with physical exercise in relation to heart attack risk; and 6. search for associations between life style and other specific chronic diseases, fatal and nonfatal. Two-page mail questonnaires are used to log physical activity patterns, social habits, and health status of college alumni. Responses supplement data already compiled from college physical examination and other records (1916-1950) investigative and followup mail questionnaires (1962 or 1966, 1972, 1977 or 1978), and official death certificates (1916-date).